[clang] [Clang] Qualified functions can't decay into pointers (PR #90353)

[Mital Ashok via cfe-commits]

MitalAshok wrote:

> https://cplusplus.github.io/CWG/issues/713.html

This one is entirely editorial: it adds a note and edits another note. I've added a test for what the note says

> https://cplusplus.github.io/CWG/issues/1417.html

I'm not sure that this DR actually changes anything. It seems pointers/references to function pointers were ill-formed before and remain ill-formed afterwards.

> https://cplusplus.github.io/CWG/issues/1584.html

Clang 7 implemented the 2015 resolution of this: 413f3c55955537552b556a556d678d5756a9f16b

https://github.com/llvm/llvm-project/pull/90353